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Chemical mapping of DNA and counter-ion content inside phage by energy-filtered TEM

Nevsten, Pernilla LU ; Evilevitch, Alex LU and Wallenberg, Reine LU (2012) In Journal of Biological Physics 38(2). p.229-240
Abstract
Double-stranded DNA in many bacterial viruses (phage) is strongly confined, which results in internal genome pressures of tens of atmospheres. This pressure is strongly dependent on local ion concentration and distribution within the viral capsid. Here, we have used electron energy loss spectroscopy (EELS), energy-filtered TEM (EFTEM) and X-ray energy dispersive spectroscopy to provide such chemical information from the capsid and the phage tail through which DNA is injected into the cell. To achieve this, we have developed a method to prepare thin monolayers of self-supporting virus/buffer films, suitable for EELS and EFTEM analysis. The method is based on entrapment of virus particles at air-liquid interfaces; thus, the commonly used... (More)
Double-stranded DNA in many bacterial viruses (phage) is strongly confined, which results in internal genome pressures of tens of atmospheres. This pressure is strongly dependent on local ion concentration and distribution within the viral capsid. Here, we have used electron energy loss spectroscopy (EELS), energy-filtered TEM (EFTEM) and X-ray energy dispersive spectroscopy to provide such chemical information from the capsid and the phage tail through which DNA is injected into the cell. To achieve this, we have developed a method to prepare thin monolayers of self-supporting virus/buffer films, suitable for EELS and EFTEM analysis. The method is based on entrapment of virus particles at air-liquid interfaces; thus, the commonly used method of staining by heavy metal salts can be avoided, eliminating the risk for chemical artifacts. We found that Mg2 + concentration was approximately 2-4 times higher in the DNA-filled capsid than in the surrounding TM buffer (containing 10 mM Mg2 + ). Furthermore, we also analyzed the DNA content inside the phage tail by mapping phosphorus and magnesium. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Energy-Filtered Transmission Electron Microscopy (EFTEM), Electron, Energy Loss Spectroscopy (EELS), Magnesium, Phage lambda, Spermine, Chemical mapping
in
Journal of Biological Physics
volume
38
issue
2
pages
229 - 240
publisher
Kluwer
external identifiers
  • wos:000302868400003
  • scopus:84863859518
ISSN
0092-0606
DOI
10.1007/s10867-011-9234-8
language
English
LU publication?
yes
id
7c4fc0a4-cc5d-462a-baff-1c31dcd0c7c5 (old id 2571307)
date added to LUP
2012-05-29 15:50:17
date last changed
2017-01-01 05:28:13
@article{7c4fc0a4-cc5d-462a-baff-1c31dcd0c7c5,
  abstract     = {Double-stranded DNA in many bacterial viruses (phage) is strongly confined, which results in internal genome pressures of tens of atmospheres. This pressure is strongly dependent on local ion concentration and distribution within the viral capsid. Here, we have used electron energy loss spectroscopy (EELS), energy-filtered TEM (EFTEM) and X-ray energy dispersive spectroscopy to provide such chemical information from the capsid and the phage tail through which DNA is injected into the cell. To achieve this, we have developed a method to prepare thin monolayers of self-supporting virus/buffer films, suitable for EELS and EFTEM analysis. The method is based on entrapment of virus particles at air-liquid interfaces; thus, the commonly used method of staining by heavy metal salts can be avoided, eliminating the risk for chemical artifacts. We found that Mg2 + concentration was approximately 2-4 times higher in the DNA-filled capsid than in the surrounding TM buffer (containing 10 mM Mg2 + ). Furthermore, we also analyzed the DNA content inside the phage tail by mapping phosphorus and magnesium.},
  author       = {Nevsten, Pernilla and Evilevitch, Alex and Wallenberg, Reine},
  issn         = {0092-0606},
  keyword      = {Energy-Filtered Transmission Electron Microscopy (EFTEM),Electron,Energy Loss Spectroscopy (EELS),Magnesium,Phage lambda,Spermine,Chemical mapping},
  language     = {eng},
  number       = {2},
  pages        = {229--240},
  publisher    = {Kluwer},
  series       = {Journal of Biological Physics},
  title        = {Chemical mapping of DNA and counter-ion content inside phage by energy-filtered TEM},
  url          = {http://dx.doi.org/10.1007/s10867-011-9234-8},
  volume       = {38},
  year         = {2012},
}